For The Courteous Ninjas to play something they practiced prior to the performance is more of a threat than a request. The Ninjas have no time to practice: they're superheroes. And superheroes should not be spending time practicing music. They should either be A) protecting citizens and solving crimes or B) rocking to many adoring fans. In that order.
As the story goes, The Ninjas were poised to be the next big thing in both the Mainstream Vigilante Superhero Market and the Recording Industry. They did both so well that they could have been huge in either. But they were, true to their teachings, but humble men and decided to leave one of the fields and focus on either A) only protecting citizens and solving crimes or B) only rocking to many adoring fans and writing kick-ass pop songs.
On the evening proceeding their historic decision, The Courteous Ninjas' studio/pad/lair was attacked by a gang of jealous superheroes or jealous super-rival bands. No one was sure. The official case was inconclusive.
The Ninjas knew what they had to do.
The Courteous Ninjas were forced to give up the muse of songwriting for several years in order to avenge this attack. Though they tried to hold on to the 'rocking to many adoring fans' part, the wave of crime necessitated a stronger focus on both protecting citizens and solving crimes.
As a result, The Courteous Ninjas' pop sensibility was stolen from for several decades. Their songs became hits for other, less talented and much less super acts. "They" may call it inspiration, but The Ninjas call it theft!
The Courteous Ninjas' claim to the authorship of most of your "favorite numbers,"--despite numerous legal, philosophical, temporal, and biological facts stating otherwise--is one so preposterous, it must be true.
Having solved most crime, The Courteous Ninjas once again emerged in the late 1990s, after a long scandal-ridden absence from the spotlight, to take back their songs with very select performances in very super-select locales. They still made no time to practice. Honestly.